The present invention relates to a packaging container and packaging material therefor.
Conventionally, in order to reduce the weight and cost, a packaging container containing liquid food (contents) such as milk or soft drink is manufactured from a packaging material including a paper substrate and resin layers formed so as to sandwich the paper substrate.
A method of manufacturing such packaging containers comprises a first step of forming a semi-finished package as an intermediate product, and a second step of forming a final package.
In the first step, a sheet-shaped packaging material is transported longitudinally and the opposite transverse edges of the packaging material are sealed together in the longitudinal direction (longitudinal sealing) so as to form the packaging material into a tubular shape, and liquid food is charged therein. Subsequently, the tubular packaging material is sealed in a transverse direction (transverse sealing) at predetermined intervals in order to form strip-shaped sealed portions, and is then cut at the sealed portions. Thus is formed a pillow-shaped, semi-finished package that contains liquid food and has a predetermined thickness.
In the second step, the semi-finished package is formed into a polygonal columnar shape such as a hexagonal prism or an octagonal prism, and a pair of flaps are formed at either end of the semi-finished package. Subsequently, the flaps at either end are folded so as to face each other and welded to the corresponding end-surface portion to complete the final package (see Japanese Patent Application Laid-Open (kokai) No. 7-187181).
A rupturable portion is formed in advance in the upper end-surface portion of the final package. The rupturable portion is easily ruptured upon receipt of an external force. Further, a spout open/close member formed of a resin is bonded to the final package at a position corresponding to the rupturable portion. In this manner, a packaging container is formed.
However, in such a packaging container, since two flaps are welded to the upper end-surface portion, it is difficult to secure a sufficiently large area where the spout open/close member is bonded. Therefore, the bonding area between the spout open/close member and the upper end-surface portion decreases, resulting in failure to bond the spout open/close member with sufficient adhesion force. In addition, since projections and depressions are formed on the upper end-surface portion, the appearance of the packaging container deteriorates. Moreover, if the spout open/close member is bonded to a narrow area, the spout open/close member becomes difficult to operate, with the result that the packaging container cannot be opened with ease.
A large-sized spout open/close member that covers the entire upper end-surface portion may be used. However, in this case, the degree of freedom in designing the size, shape, etc., of the spout open/close member decreases.
An object of the present invention is to solve the problems involved in conventional packaging containers and to provide a packaging container and packaging material therefor which can secure a sufficient area for bonding a spout open/close member, which enable the spout open/close member to be bonded with sufficient adhesion force, which i provide an improved appearance, and which increase the degree of freedom in designing the spout open/close member.
To achieve the above object, a packaging container according to the present invention comprises: a pair of seal portions; at least five side-surface panel portions for forming a circumferential wall; an end-surface panel portion disposed between the seal portion and the side-surface panel portions and adapted to form a polygonal end-surface portion in cooperation with an intermediate portion of the seal portion; and flap portions projected, together with end portions of the seal portion, from the end-surface panel portion, each of the flap portions being bent toward a specified panel portion among the side-surface panel portions and-being welded to the specified panel portion.
In this case, since the flap portions are welded to the specified panel portions, and the end-surface portion is thus made substantially flat, a sufficiently large flat area can be secured on the end-surface portion. Since no projection or depression is formed on the end-surface portion, the appearance of the packaging container can be improved, and a sufficiently large area for bonding the spout open/close member can be secured.
Further, the bonding area between the spout open/close member and the end-surface portion can be increased without use of a large spout open/close member that covers the entire end-surface portion, so that the spout open/close member can be bonded with sufficient adhesion force. Moreover, since the end-surface portion is not prone to accumulation of dust, the packaging container is sanitary. In addition, the appearance of the packaging container can be improved, and the degree of freedom in designing the size, shape, etc., of the spout open/close member can be increased.
Another packaging container according to the present invention further comprises a first folding portion formed between each of the flap portions and corresponding one of the specified panel portions, and a second folding portion formed between the end-surface panel portion and each side-surface panel portion adjacent to each of the specified panel portions.
In still another packaging container according to the present invention, each of the first and second folding portions has a lower folding portion formed adjacent to the side-surface panel portion and being superposed on the side-surface panel portion, as well as an upper folding portion formed adjacent to the lower folding portion and being superposed on the lower folding portion.
In still another packaging container according to the present invention, the upper folding portion and the lower folding portion of the first folding portion each have a rectangular shape, and the upper folding portion and the lower folding portion of the second folding portion each have a triangular shape.
In still another packaging container according to the present invention, crush portions are formed in regions surrounded by the flap portions, the upper folding portions of the first folding portions, and the upper folding portions of the second folding portions, and the crush portions are crushed when the flap portions are bent toward the specified panel portions.
In this case, since the crush portions are crushed when the flap portions are bent toward the specified panel portions, the upper end portions of the flap portions do not project far from the side-surface panel portions. Accordingly, the appearance of the packaging container can be improved.
A packaging material for a packaging container according to the present invention comprises: a pair of seal portions; at least five side-surface panel portions for forming a circumferential wall; an end-surface panel portion disposed between the seal portion and the side-surface panel portions and adapted to form a polygonal end-surface portion in cooperation with an intermediate portion of the seal portion; and flap portions projected, together with end portions of the seal portion, from the end-surface panel portion, each of the flap portions being bent toward a specified panel portion among the side-surface panel portions and being welded to the specified panel portion.
Another packaging material for a packaging container according to the present invention further comprises a first folding portion formed between each of the flap portions and corresponding one of the specified panel portions, and a second folding portion formed between the end-surface panel portion and each side-surface panel portion adjacent to each of the specified panel portions.
In still another packaging material for a packaging container according to the present invention, each of the first and second folding portions has a lower folding portion formed adjacent to the side-surface panel portion and being superposed on the side-surface panel portion, as well as an upper folding portion formed adjacent to the lower folding portion and being superposed on the lower folding portion.
In still another packaging material for a packaging container according to the present invention, the upper folding portion and the lower folding portion of the first folding portion each have a rectangular shape, and the upper folding portion and the lower folding portion of the second folding portion each have a triangular shape.
In still another packaging material for a packaging container according to the present invention, crush portions are formed in regions surrounded by the flap portions, the upper folding portions of the first folding portions, and the upper folding portions of the second folding portions, and the crush portions are crushed when the flap portions are bent toward the specified panel portions.